I'm definitely not serious, lol.
Brian knows I'm just busting his balls. I'm truly amazed by the amount of time and dedication he has put into making it and more importantly, the research he has done with it.

It really doesn't look as bad as he thinks it does either, IMO. Function over form anyway.

Yesyes! I made a couple nice revisions in April and May, but have unfortunately have just been too busy to do a further writeup! Part of that can be blamed on prelude2perfect (above) for frying his clutch TWICE and forcing me to help replace it TWICE haha

NO major design changes, but I needed to find a way to make the side skirts and edges of the outside edges of the diffuser stay straight and not 'ripple' after bottoming out and scraping the diffuser strakes on the ground. In a nutshell, after a couple months of normal use (bottoming out over speed bumps/alignment racks, etc) the horizontal piece of the side skirts started to get wavy, as well as the side edges of the diffuser. I've remedied the diffuser design well, but the side skirts are being difficult.

The challenge for the side skirts is to have all of the requirements:
-1 single piece of material for horizontal side skirt, preferably under 3/16" thick
-1 single piece of material for the vertical side skirt, thickness does not matter (includes pivot point to make the jacking point accessible)
-able to remove vertical skirt from outside of car with car on the ground (use spider nuts)
-Will not crack or permantently bend as a result of a mild bottom-out
-**Horizontal skirt will not permanently distort or ripple as a result of the vertical skirt being compressed from bottoming out.

I've tried a handful of materials, and it all looks great until the first time scraping or bottoming out. Some materials look cheap but don't permanently bend, some look great but will crack or bend at first scrape.

Worse comes to worse- the vertical side skirts will just need to be removed for anything other than track use or when they are sure not to bottom out.

I also have been playing around with carbon fiber, but there are even more quality/durability challenges with that. Plus, the new Airbus A350 has caused a world-wide shortage of carbon fiber

Yesyes! I made a couple nice revisions in April and May, but have unfortunately have just been too busy to do a further writeup! Part of that can be blamed on prelude2perfect (above) for frying his clutch TWICE and forcing me to help replace it TWICE haha

NO major design changes, but I needed to find a way to make the side skirts and edges of the outside edges of the diffuser stay straight and not 'ripple' after bottoming out and scraping the diffuser strakes on the ground. In a nutshell, after a couple months of normal use (bottoming out over speed bumps/alignment racks, etc) the horizontal piece of the side skirts started to get wavy, as well as the side edges of the diffuser. I've remedied the diffuser design well, but the side skirts are being difficult.

The challenge for the side skirts is to have all of the requirements:
-1 single piece of material for horizontal side skirt, preferably under 3/16" thick
-1 single piece of material for the vertical side skirt, thickness does not matter (includes pivot point to make the jacking point accessible)
-able to remove vertical skirt from outside of car with car on the ground (use spider nuts)
-Will not crack or permantently bend as a result of a mild bottom-out
-**Horizontal skirt will not permanently distort or ripple as a result of the vertical skirt being compressed from bottoming out.

I've tried a handful of materials, and it all looks great until the first time scraping or bottoming out. Some materials look cheap but don't permanently bend, some look great but will crack or bend at first scrape.

Worse comes to worse- the vertical side skirts will just need to be removed for anything other than track use or when they are sure not to bottom out.

I also have been playing around with carbon fiber, but there are even more quality/durability challenges with that. Plus, the new Airbus A350 has caused a world-wide shortage of carbon fiber

Thanks for the update!
I know Turugara, we've both been following this thread since you've started posting.

I would definitely suggest making anything that has the chance of bending easy to remove for non-track use. I would have no problem at all spending 15 or 20 minutes adding my aero parts for the track.
Like you said, pieces that look cheap can actually work better. I used to have C5 and C6 Corvettes and the front air deflecter for the radiator was made of cheap plastic that bent when hit by speed bumps/driveways, but would bounce back. Once it got too bad, you just replaced it. It cost only $65 and would last several years!
I'd probably remove the rear diffuser as well for street driving. No sense in keep it on and taking the chance of it getting banged up for no good reason.

Thanks for the update!
I know Turugara, we've both been following this thread since you've started posting.

I would definitely suggest making anything that has the chance of bending easy to remove for non-track use. I would have no problem at all spending 15 or 20 minutes adding my aero parts for the track.
Like you said, pieces that look cheap can actually work better. I used to have C5 and C6 Corvettes and the front air deflecter for the radiator was made of cheap plastic that bent when hit by speed bumps/driveways, but would bounce back. Once it got too bad, you just replaced it. It cost only $65 and would last several years!
I'd probably remove the rear diffuser as well for street driving. No sense in keep it on and taking the chance of it getting banged up for no good reason.

Yeah for sure! One of the coolest things about the diffuser and splitter is that I've made it as easy as pie to install and remove (after the inital setup, of course). It's all bolted together using welded nuts or speed nuts, so you never have to snake your arm above the diffuser to thread a nut onto a bolt or anything. You can actually remove the entire diffuser with just a 8 and 10mm socket and a 4mm allen, and when you use an electric impact it couldn't be faster. The only visible item left would be the rear cross brace which will require a 11mm wrench, but otherwise it'd all be done with one hand. The splitter is the same way with the exception of the 4 cables. Side skirts are not so easy- they actually require removing the side skirts, which isn't all that hard but just not as *easy*

Quote:

Originally Posted by TSM330i

BrianMN
On another note: Do you have front brake cooling ducts?
I noticed you don't have any fog lights in your front bumper. I'm most probably going to be doing that very soon.

I used to have 2.5" aeroduct hosing from the lower grills to the dust shield of the rotors, but those were another track-only system, as turning the wheels more than half way would crush the hoses. Now that I have two massive setrab oil coolers that take up the entire area in front of the wheels, I need to pull air from underneath, which is one of my recent mods this summer. I've made a set of GT2 style brake ducts which swoop air from under the splitter and direct it to the rotor. It won't be nearly as effective as a direct ram-air hose leading to the center of the rotor, but it's better than nothing. Even with the cooling, I think I'm overworking the brakes. (one piece steel rotors with vertical vanes, stock calipers with DTC-70s). Rotor temps after 25-30 minute sessions are 650* at BIR, which is a high speed track but not horrible for brakes, and 750*+ at Road America, which is hard on engines and brakes.

Brian, you sure know what you're talking about! I was recently watching a documentary on F1 cars and the design of the body and aero and their purpose. In your OP, everything I read was spot on including keeping the low pressure from under the car with the side skirts. F1 cars were designed with aircraft technology and aerodynamics in mind. Great work and surely keep it up. Amazing car!

Myself, Turugara and the Bimmerworks Race Team are working with Brian to get a full aero kit for our cars. He has been back and forth with all of us in the development of these pieces. It's a little easier for my car since I'm also driving an e90 (same as Brian), but he's borrowing an e92 so he can properly setup the e92.

Thanks for all your efforts Brian! We can't wait to get our cars out on the circuit to see the difference.

This is some awesome stuff! I took the time to read through this, it appears all that crap they taught me in fluid dynamics is kinda true haha. I'll be following this thread no to learn more about all of this

for a great thread based on facts and lots of testing. This is what E90post is all about - enthusiasts helping each other get down the learning curve faster.

BTW, the only reason I found this is because a friend of mine with a Lotus Exige is doing the same and fabricating his own underbody aero kit and he was asking me some questions b/c of my engineering background. I told him that aero principles are basically guides, but that it's an empiracle science; so I did a search and viola. Just a note, but my friend is the reason I'm looking to get into tracking too.

How about an update, Brian? Depending on how my first track event goes, I may be interested in purchasing a kit from you in the next couple of months.

All those interested in the full aero kit for an e90, please pm me. I was originally going to install the kit on my car, but I've had a complete change with what I'm going to be doing with my car. I've purchased a Z4 coupe that I'm turning a full blown race car and will be getting my competition license, hence, I won't be tracking my car.

PM if you're interested in purchasing the kit for the e90. I have it already, but it's never been installed. Brian has been fantastic at getting us information on the install. We are still going to be installing two kits on coupes in the near future.